Single commutation vertical wheel marking machine

ABSTRACT

A marking wheel for marking metal or plastic tags and the like employing a rotary marking wheel having marking characters on the periphery which is continuously rotated and, upon depressing of an appropriate key upon a keyboard, is caused to stop. Marking is established by the raising of a worktable driven through a magnetic clutch to engage the tag with the marking wheel. The clutch in stopping of the continuously rotating marking wheel is activated by an electrical circuit which comprises a segment of a commutator stator on a printed circuit board which completes the circuit upon being contacted by a continuously driven rotor. The circuit employs a silicon control rectifier for extremely rapid completion of the electrical circuit upon the depression of the desired key on the keyboard. The completion of the circuit through the appropriate segment on the commutator further actuates a pawl to engage the appropriate ratchet tooth on a ratchet wheel keyed to the shaft of the marking wheel to stop the marking wheel for the marking operation.

llnited States Patent [191 Schacht SINGLE COMMUTATION VERTICAL WHEELMARKING MACHINE [76] Inventor: Roy Arthur Schacht, 744 Des Peres Rd.,St. Louis, Mof63l3 l 7 V v [22] Filed: May 3, 1973 [21] Appl. No.:356,732

Related 1.1.8. Application Data 63] Continuation of Ser. No. 148,463,June 1, 1971,

abandoned.

[52] US. Cl 197/6.4, 197/49 [51] Int. Cl B41j 1/22 [58] Field of Search197/49, 6.4, 6.5,

[56] References Cited UNITED STATES PATENTS 2,664,985 1/1954 Schachtl97/6.5

3,232,404 2/1966 Jones 197/49 3,227,258 1/1966 Pannier et al.. l97/6.6

3,589,494 6/1971 Gloess 197/49 X 3,330,397 7/1967 Schwartz et a1.l97/6.7

3,306,416 2/1967 Dahlin et a1. l97/6.6

Rudisch et al. l9-'7/6.6

[451 Jan. 15, 1974 Primary ExaminerRobert E. Pulfrey AssistantExaminer--R. T. Rader AttorneyGlenn K. Robbins [57] ABSTRACT A markingwheel for marking metal or plastic tags and the like employing a rotarymarking wheel having marking characters on the periphery which iscontinuously rotated and, upon depressing of an appropriate key upon akeyboard, is caused to stop. Marking is established by the raising of'a'worktable driven through a magnetic clutch to engage the tag with themarking wheel. The clutch in stopping of the continuously rotatingmarking wheel is activated by an electrical circuit which comprises asegment of a commutator stator on a printed circuit board whichcompletes the circuit upon being contacted by a continuously drivenrotor. The circuit employs a silicon control rectifier for extremelyrapid completion of the electrical circuit upon the depression of thedesired key on the keyboard. The completion of the circuit through theappropriate segment on the commutator further actuates a pawl to engagethe appropriate ratchet tooth on a ratchet wheel keyed to the shaft ofthe marking wheel to stop the marking wheel for the marking operation.

6 Claims, IODrawing Figures PATENTEBJAN I 5 I974 sum aur SINGLECOMMUTATION VERTICAL WEEI. MARKING MACHINE This is a continuation ofapplication Ser. No. 148,463, filed June l, 1971 now abandoned.

SUMMARY OF THE INVENTION In the past, various types of marking wheelshave been devised for physically imprinting on metal or plastic tags andthe like. One such marking wheel has been shown in my U.S. Pat. No.2,664,985 which uses a rotary marking or imprinting wheel withcharacters on the periphery of the wheel which are caused to printagainst a work piece raised into printing relation by a reciprocal worktable. The continuously rotating marking or printing wheel is stopped inthe printing operation by the engagement of an electromagneticallyoperated pawl against a ratchet wheel keyed to the shaft of the printingwheel. Such wheels as my prior marking machine shown in US. Pat. No.2,664,985 required two solenoid operated pawls because the relayelectrical system could not be devised to be fast enough to operate witha single pawl on the ratchet wheel.

By means of this invention, there has been provided an improved markingwheel in which the electrical system utilizes a printed circuit boardand a direct current circuit utilizing a silicon control rectifier, i.e.SCR which is energized by a small voltage such as two volts establishedwhen a marking key is depressed. Depression of the key sends a signalout to a commutator segment of the printed circuit commutator stator tothe gate of the SCR which is tripped to establish current to themagnetic actuator for actuating the pawl to stop the ratchet wheel andthe associated printing wheel and also to actuate a clutch actuator toturn the work table shaft one revolution. The operation of the clutchconnects the shaft to the motor to move a rotary cam against the worktable to raise and lower it in the aforesaid cycle and revolution. Bythe utilization of the printed circuit commutator and the SCR controlcircuit the switching speed is greatly increased while space andmaintenance requirements are greatly decreased.

The control circuit established'by this invention is extremely rapid inresponse and a single pawl can be employed with a single ratchet wheeelwhereas with my 1 prior machine, one tooth of the ratchet was used forevery two characters and twomagnetic actuators and pawls were requiredto be employed. Thus half as many teeth on the ratchet wheel wereemployed as the characters on the marking wheel on the machine whichgave more space and allowed the actuator more time to fall in place tostop the ratchet wheel. Thus by the instant invention with the morerapid response, through the improved electrical system provided, thespeed of operation is greatly multiplied and, as an example, works aboutfour times as fast.

Further, by the instant invention and the improved electrical circuit,protective circuits are employed to prevent the back voltage from themagnetic pawl actuator and the magnetic clutch solenoid actuator fromestablishing damaging voltages through the silicon control rectifier andthe direct current rectifier. Such a circuit is also employed in thede-energizing switch.

In addition, a condenser circuit is employed to provide a charge when anoperator provides only a light touch or momentary depressing of the keybefore the rotor and the commutator establish contact with theassociated commutator segment. This charge, when contact is ultimatelymade by the rotor with the segment, triggers the circuit to tire or tripthe gate to the SCR to establish the actuating circuit just as if a longtouch were employed on the marking keys.

The electric circuit uses direct current provided by the direct currentrectifier and the silicon control rectifier so that the keyboard controlcircuit operates at a very low voltage. Actually the keyboard simplykeys or triggers the gate of the SCR which in turn handles the highervoltages required to operate the magnetic actuators for the ratchetwheel and the clutch. The SCR once gated, continued to pass current tothe magnetic actuators until the completion of the marking cycleeffected by the operation of the de-energizing switch which is operatedby a lobe in the cam shaft associated with the work table to break theload circuit momentarily, and to set up the circuit for another markingoperation.

The machine, through the electrical circuit provided, can be controlledby a tape or card reader and a translator connected so as to read thecard or tape and send the signals read into the translator where theywill be translated into a single impulse which can be directed to theactuators of the machine through the various segments of the commutator.

The above features are objects of this invention and further objectswill appear in the detailed description which follows and will beotherwise apparent to those skilled in the art.

For the purpose of illustration, there is shown in the accompanyingdrawings a preferred embodiment of the instant invention. It is to beunderstood that these drawings are for the purpose .of example only andthat the invention is not limited thereto.

IN THE DRAWINGS FIG. 1 is a view in side elevation taken from the leftside of the machine;

FIG. 2 is an enlarged fragmentary view in rear elevation of the machine;

FIG. 3 is a view in cross-section taken on the line 3-3 of FIG. 1;

FIG. 4 is a view in section taken on the line 44 of FIG. ll;

FIG. 5 is a top plan view ofthe printed circuit board used on thecommutator;

FIG. 6 is a bottom plan view of the printed circuit board;

FIG. 7 is an enlarged fragmentary top plan view of the rear of themachine showing the printed circuit board and rotor cage attached to themarking wheel shaft;

FIG. 8 is a view in cross section taken on the line 88 of FIG. 7;

FIG. 9 is a view in section taken on the line 99 of FIG. 8 showing therotor wiper blade in contact with one of the commutator segments; and

FIG. 10 is a schematic diagram of the electrical circuit employed forthe marking machine.

DESCRIPTION OF THE INVENTION The marking wheel of this inventiongenerally identified by the reference numeral 20 in. FIG. 1. It is com-The printing wheel 24 as well as the work table and keyboard are thesame general construction as described in my aforesaid U.S. Pat. No.2,664,985. Thus the printing wheel 24 has printing characters 30associated on its periphery and the wheel is driven by a shaft 32connected to a ratchet wheel 34 and to the motor through a frictionclutch and driven by pulley belt 35. A magnetically operated pawl 36 isadapted to engage the teeth of the ratchet wheel and stop the wheelagainst the force of friction clutch 38. The pawl is actuated by asolenoid 40.

The work table 26 is pivotally supported from the machine by a yoke. 42and is adapted to be raised and lowered by the revolution of rotary cam44 which contacts a thrust bar 45 at the bottom of the table. The cam 44is connected to the cam shaft 46 which is driven only one revolution inthe marking operation by means of clutch 48 connected to the motor andwhich is actuated by clutch actuator 50 operated by solenoid S2.

A de-energizing switch to de-energize the circuit and signal thecompletion of the single revolution of the cam shaft and markingoperation is best shown in FIG. 3 where a contact button switch 54 isshown in juxtaposition to the cam 444.

The aforementioned components are identical in construction with theprinting wheel and work table and actuating mechanism described in myaforementioned U.S. Pat. No. 2,664,985.

The control circuit for my marking wheel is provided by a printedcircuit board 60 best shown in FIGS. 4 through 8. This printed circuitboard houses the commutator segments in a stator 62 and a rotor 64supported by a rotor cage 66 having a support hub 67 on one side of theprinted circuit board and a support cage 68 on the reverse side of thecircuit board. The rotor cage and support cage are in the form ofshallow dishshaped support members which are connected to one anotherthrough the circuit board by bolts and are of transparent plastic sothat the operation and contact with the rotor with the commutatorsegment can be easily read and inspected for registration andadjustment.

Each of the commutator segments is connected by a printed circuit lead69 to a buss bar 70 with approximately one-half of the commutatorsegment leads being shown on the top of the printed circuit board andthe remaining half being shown on the reverse side.

A connecting sleeve 72 fits frictionally over the buss bar 70 so thatleads can be connected to the appropriate keys 74 on the switchboard,each one associated with a commutator segment. The keys are conventionalnormally open keys of the same type as generally disclosed in my priorU.S. Pat. No. 2,664,985 and, upon being depressed, close through aspring-operated switch a circuit between the key and the printed circuitto the associated commutator segment so that, as will later bedescribed, when the rotor contacts the associated commutator segment, afiring circuit is provided into the SCR to establish energizing circuitto the coils of the magnetic actuators for the ratchet wheel pawl andcam shaft clutch.

The electrical circuit is shown schematically in FIG. 9. Alternatingcurrent is provided to the circuit through leads 80 and 82 and throughan on-off switch 84 is introduced to rectifier bridge 86 consisting offour silicon diodes through leads 88 and 90. A resistor 92 of 130 ohmsacts as a current limiting resistor to minimize the danger of voltagesurges to the silicon rectifier and the silicon diodes of the rectifierbridge.

The rectifier bridge is connected by lead 94 to the common buss bar 70.This buss bar is connected to the individual circuit leads to theindividual keys 74 on the keyboard which, as aforementioned, are in thenormally open position and upon being depressed establish a circuit tothe commutator segments 62 on the printed circuit board. The rotor 64 isconnected to a voltage divider consisting ofa 7.5 K resistor 96 and a lK resistor 98. As the common post 100 a lead 102 takes off two volts tothe gate of the silicon control rectifier 104. This rectifier isconnected by leads 106 to post 108 which, in turn, is connected by lead110 to resistor 98. The silicon control rectifier establishes a highervoltage circuit by lead 112 to the magnetic pawl actuator for theratchet wheel through solenoid 40 and is connected in series throughlead 114 to the solenoid 52 for the cam shaft clutch actuator 50. Thecircuit is in series with the de-energizing switch 54 which is normallyclosed but is momentarily opened at the completion of the single cyclemovement of the work table to signal the end of the marking operation.

In order to provide a protective means for the silicon control rectifierfrom the high back voltage from the coils for the magnetic pawl actuatorand the cam shaft actuator, a resistor 116 and condenser 118 and diode120 are provided. This establishes a protective circuit to prevent highback emf voltages from damaging the silicon control rectifier. Thiscircuit functions much in the nature of an arc suppressor switch.

Likewise for the de-energizing switch 54 a protective device in the formof condenser 120 and resistor 122 connected across the de-energizingswitch are provided. Thus, where a large back surge of voltage isestablished through the coils instead of jumping across the contacts ofthe de-energizing switch, the condenser absorbs this voltage and leaksit out slowly through the resistor.

A condenser 124 is connected across the keys to provide a safety circuitto insure firing of the silicon control rectifier where the operatoronly momentarily depresses the marking key 74. In such a case where anextremely light touch is employed, which is not long enough for therotor to establish contact with the keys associated commutator segment,the condenser establishes an electrical charge so that when the contactis established, there will be some energy which discharges to completethe circuit to the gate of the SCR to provide operation of the magneticactuator for the ratchet wheel pawl and the cam shaft clutch to effectthe marking operation.

OPERATION The marking wheel of this invention is simply operated byfirst closing the on-off switch 84. This provides a source of power tothe electrical circuit to drive the rotary marking wheel 24 and tooperate the work table 26 which raises and lowers the work piece intocontact with the marking wheel to perform the marking operation upon thework piece such as a tag, metal emblem or other material to bephysically marked.

The rotary marking wheel is provided with the various marking characters30 in its periphery corresponding to letters of the alphabet, punch codecharacters and symbols, and the like, revolves constantly until it isstopped for the marking operation. It is driven through the friction orslip clutch 38 until an electrical signal is pulsed by operation of thekeyboard 28 through a corresponding stator segment 62 of the commutatoron the printed circuit board. The rotor 6 of the commutator establishesa circuit when it passes over the segment of the commutatorcorresponding to the depressed key 74 to actuate the marking wheelratchet wheel 34 by means of an electromagnetic pawl 36 which engagesthe appropriate tooth of the ratchet wheel fastened to the printingwheelshaft. The engagement of the ratchet wheel by the magnetic pawl stopsthe character wheel at the proper printing character in markingposition.

The depressing of the key also actuates the cam shaft clutch actuator50, 52 to connect the cam shaft 46 as sociated with the work table whichis driven on revolution per mark by the motor acting through themagnetic clutch. This causes the work table to be raised to applypressure between the marking wheel and the work to perform the markingoperation. it will be understood that instead of raising 'andloweringthe work table the magnetic actuator and cam shaft may be used to lowerand raise the printing wheel.

The keyboard employed has normally open switches associated with each ofthe marking keys which are connected by leads 69 to commutator segments62 corresponding to the appropriate'ratchet tooth and marking characteron the marking wheel so that when the desired key is depressed currentis directed through the commutator to the magnetic ratchet wheelactuator solenoid 40 and the cam shaft magnetic clutch solenoid 52 forthe work table causing the wheel to stop with the key selected stamp inthe marking position. This circuit also causes the cam shaft to revolve,which elevates the work table, pressing the work and the marking wheeltogether. As the cam shaft continues to revolve the cam the closing ofthe main on-off switch 8d. This is conventionally actuated from thekeyboard and connects the segments 62 of the commutatorwith the positiveside of the DC supply provided by lead 94- through the rectifier. Eachkey, as shown in the drawing, is connected with a different segment ofthe commutator stator on the printed circuit board, some being shownconnected to segments on one side of the board and the others beingconnected to segments on the reverse side of the board to make fullutilization of space. The commutator, for purpose of example, may berotating at 173 RPM and faster and, as the rotor blade 64 wipes over thesegments, it establishes a circuit upon the depressing of theappropriate key 74m complete the circuit. This circuit is establishedthrough the voltage divider composed of resistor 96 and resistor 98 toprovide a low voltage such as 2 volts to the gate of the SCR 104. Whenthe gate of the SCR is energized by the low voltage from the voltagedivider, it passes current from the positive side through the normallyclosed deenergizing switch 54 and through the cam shaft clutch actuatorsolenoid 52 for the work table drive shaft and the solenoid 52 for theratchet wheel actuator. The energization of this clutch causes a singlerevolution of the cam shaft to raise and lower the worktable through theenergizing coil of the magnetic actuator which actuates the clutch lever56 to cause the connection of the clutch to the motorv shaft.

The marking wheel actuator is connected in series with the magneticclutch actuator and through the solenoid coil 40 in the marking wheelactuator causes the pawl 36 to engage the ratchet wheel 34 connected tothe printing wheel shaft and stop the marking wheel with the appropriatemarking character in printing position to perform the printing operationwhen the work table is raised.

As the cam shaft 46 completes its one-cycle revolution, it causes theengagement of a pin that momentarily opens the normally closeddeenergizing switch 54 which deenergizes and opens the circuit to boththe marking wheel actuator and cam shaft clutch actuator to complete themarking operation. The machine is then ready for the next markingoperation upon the depressing of the desired key on the keyboard.

The source of direct current is provided by the rectifier bridge 86consisting of four silicon diodes. The rectifieris connected to aresistor 92 in series on the AC lead to provide a current limitingfactor to the SCR and the rectifier to prevent blowout-caused by voltagesurges. The resistor 116 and condenser 118 and diode 119 provide aprotective circuit to protect the SCR from high back emf voltages fromthe coils of the marking wheel actuator and the cam shaft clutchactuator from surges of power that might otherwise blow out or causedamage to these components. They operate much in the fashion of an arcsuppressor across a switch to minimize the effect of high inductiveloads to prevent arcing across the contacts. The coils of the markingwheel actuator and theactuator for the magnetic clutch have relativelyhigh reverse voltages when the circuit is shut off and the protectionafforded minimizes the damaging effect of these voltages.

A condenser 120 and resistor 122 are also connected across thedeenergizing switch 54. to provide a protective circuit for the switch.A back-surge of voltage instead of jumping across the contact so theenergizing switch will be absorbed by the condenser and then leaked outslowly through the resistor to provide protection for the switch, muchin the same fashion as described above, for the SCR and rectifier.

The condenser 1124 is provided to establish a charge whenever theoperator touches a key. As the wiper blade on the commutator comes incontact with the segment corresponding to the depressed key, thecondenser has .a charge waiting for it and this will be picked up rightaway. Thus, in the case where operators depress a key only momentarily,and before the wiper blade comes around to complete a circuit with theassociated commutator segment, thezoperator may have already releasedthe key so there is no circuit established. With the provision of thecondenser connected across the contact by the key, a charge is providedso that discharge can be effected through the segment corresponding tothe depressed key when the wiper blade rotor establishes contact toenergize the circuit through the SCR. By the provision of thiscondenser, the socalled light touch operator difficulty has beenobviated. At the faster speeds of rotation of the wiper blade rotor, thelight touch problem is minimized but, in any event, the provision of thecondenser obviates this problem.

Various changes and modifications may be made in this invention, as willbe readily apparent to those skilled in the art. Such changes andmodifications are within the scope and teaching of this invention asdefined by the claims appended hereto.

What is claimed is:

1. in a marking machine having a rotating marking wheel with markingcharacters provided at the periphery of the wheel and a work tablecarrying a work piece, means for vertically moving the work table byraising it into marking position when said wheel is in a stoppedposition, and a control means for controlling the stopping of saidmarking wheel in selected marking positions, said control means beingprovided with individual marking circuits connected to segments of acommutator stator, said commutator having a rotor adapted to wipe saidsegments and actuate an electromagnetically operated pawl engageable inselected ratchet teeth on a ratchet wheel to stop said marking wheel ina selected marking position corresponding to the selected key, theimprovement comprising means for providing a direct current to saidindividual marking circuits provided by the depressing ofa key to asilicon control rectifier to energize a magnetic actuator to actuatesaid pawl to engage the ratchet wheel to stop the marking wheel and toenergize a separate magnetic actuator to actuate said vertical movingmeans, the

commutator stator being in the form of a printed circuit.

board of rigid material and having individual printed circuit leads onboth sides of the board terminating in a buss bar formed as a tabextension on the board, said buss bar removably receiving a cable sleevefitting over said tab-extension and provided with circuit leadsregistering with the individual printed circuit leads and communicatingwith switchboard keys provided in the control means, and said commutatorsegments being formed by an electrically conductive layer materialprinted on the board.

2. The marking wheel of claim 1 in which condenser means are provided tohold an electrical charge upon momentary depressing of a selectedmarking key provided in the control means before the rotor contacts theassociated commutator segment to fire the silicon control rectifier whensaid rotor at a later time makes contact with said segment.

3. The marking wheel of claim 1 in which the rotor is joumaled in atransparent plastic cage on one side of the board providing for visualinspection of the rotor with the commutator segments and the oppositeside of the board is provided with a support cage having meansconnecting it to the rotor cage providing stability against bending ofthe printed circuit board.

4. The marking wheel of claim 3 in which the aforementioned cages aregenerally dish-shaped and enclose the commutator segments for protectionthereof.

5. The marking wheel of claim 1 in which the rotor is connected tovoltage divider means to provide a low voltage to the silicon controlrectifier upon the completion of a circuit established by the controlmeans.

6. The marking wheel of claim 1 in which said rotor is connected tovoltage divider means to provide a low voltage to the silicon rectifierupon the completion of a circuit established by the depression of aselected marking key provided in the control means, condenser meansbeing provided to hold an electrical charge upon momentary depressing ofa key before the rotor contacts the associated commutator segment tofire the silicon control rectifier when said rotor at a later time makescontact with said segment, said rotor being journaled in a transparentplastic cage on one side of the board providing for visual inspection ofthe rotor with the commutator segments, and a support cage having meansconnecting it to the rotor cage providing stability against bonding ofthe printed circuit board, said cages being generally dish-shaped toenclose the commutator segments for protection thereof.

1. In a marking machine having a rotating marking wheel with markingcharacters provided at the periphery of the wheel and a work tablecarrying a work piece, means for vertically moving the work table byraising it into marking position when said wheel is in a stoppedposition, and a control means for controlling the stopping of saidmarking wheel in selected marking positions, said control means beingprovided with individual marking circuits connected to segments of acommutator stator, said commutator having a rotor adapted to wipe saidsegments and actuate an electromagnetically operated pawl engageable inselected ratchet teeth on a ratchet wheel to stop said marking wheel ina selected marking position corresponding to the selected key, theimprovement comprising means for providing a direct current to saidindividual marking circuits provided by the depressing of a key to asilicon control rectifier to energize a magnetic actuator to actuatesaid pawl to engage the ratchet wheel to stop the marking wheel and toenergize a separate magnetic actuator to actuate said vertical movingmeans, the commutator stator being in the form of a printed circuitboard of rigid material and having individual printed circuit leads onboth sides of the board terminating in a buss bar formed as a tabextension on the board, said buss bar removably receiving a cable sleevefitting over said tab-extension and provided with circuit leadsregistering with the individual printed circuit leads and communicatingwith switchboard keys provided in the control means, and said commutatorsegments being formed by an electrically conductive layer materialprinted on the board.
 2. The marking wheel of claim 1 in which condensermeans are provided to hold an eLectrical charge upon momentarydepressing of a selected marking key provided in the control meansbefore the rotor contacts the associated commutator segment to fire thesilicon control rectifier when said rotor at a later time makes contactwith said segment.
 3. The marking wheel of claim 1 in which the rotor isjournaled in a transparent plastic cage on one side of the boardproviding for visual inspection of the rotor with the commutatorsegments and the opposite side of the board is provided with a supportcage having means connecting it to the rotor cage providing stabilityagainst bending of the printed circuit board.
 4. The marking wheel ofclaim 3 in which the afore-mentioned cages are generally dish-shaped andenclose the commutator segments for protection thereof.
 5. The markingwheel of claim 1 in which the rotor is connected to voltage dividermeans to provide a low voltage to the silicon control rectifier upon thecompletion of a circuit established by the control means.
 6. The markingwheel of claim 1 in which said rotor is connected to voltage dividermeans to provide a low voltage to the silicon rectifier upon thecompletion of a circuit established by the depression of a selectedmarking key provided in the control means, condenser means beingprovided to hold an electrical charge upon momentary depressing of a keybefore the rotor contacts the associated commutator segment to fire thesilicon control rectifier when said rotor at a later time makes contactwith said segment, said rotor being journaled in a transparent plasticcage on one side of the board providing for visual inspection of therotor with the commutator segments, and a support cage having meansconnecting it to the rotor cage providing stability against bonding ofthe printed circuit board, said cages being generally dish-shaped toenclose the commutator segments for protection thereof.